1. Field of the Invention
The present disclosure relates to a data distribution device and imaging apparatus for distributing specific data such as video data via a network to an external device connected to the network.
2. Background Art
A communication device is known that, when it connects to a network, acquires routing information including default route information using a communication protocol such as a DHCP (Dynamic Host Configuration Protocol) or PPP (Point to Point Protocol), and performs automatic setting. This communication device does not require the network setting by a user.
The routing information means the information indicating a transfer route of an IP (Internet Protocol) packet (which means data in a form capable of being handled on a network, and is referred to also as “packet”) on a network. The default route information means the routing information that indicates an IP address (serving as the transfer destination of the IP packet) used when the transmission source does not know the transfer destination of the IP packet. For example, upon acquiring default information, a device as the transmission source of the IP packet sets a default route in accordance with the default route information, and transfers, along the default route, the IP packet whose transfer destination is not known.
A computer terminal (simply referred to also as “terminal”) is known that includes a plurality of communication devices including a first communication device and a second communication device and can be connected to a plurality of networks. This terminal can be connected to one network (e.g. first network) using the first communication device, and can be connected to another network (e.g. second network) using the second communication device.
However, this terminal acquires routing information from one network and performs automatic setting, so that the communication via another network is sometimes disabled. For example, the terminal is connected to the first network via the DHCP using the first communication device. In this state, the terminal can perform communication via the first network. Then, the terminal is connected to the second network via the DHCP using the second communication device. In this case, the routing information set when the terminal is connected to the first network is updated to the routing information acquired via the second communication device. Therefore, the terminal transmits all of subsequent data (transmission packets) via the second network.
Thus, when the routing information (default route) is automatically updated, the following problems can occur, for example.
(1) Although the communication state where specific data is transmitted (for example, video distribution by streaming) via a first network (for example, network allowing high-speed communication) is intended to be kept, the default route is changed so that the communication is performed via a second network (for example, a network having a relatively low communication speed). Therefore, a trouble (for example, a temporary halt of streaming) occurs in transmission of the specific data.(2) This terminal cannot communicate, via a second network, with a terminal as the communication partner with which this terminal has communicated via a first network. Here, the first network is a public line network such as LTE (Long Term Evolution), and the second network is LAN (Local Area Network) that is not connected to the Internet, for example. Therefore, the switching of the default route from the first network to the second network disables the data transmission (e.g. video distribution) to the terminal as the communication partner.
Unexamined Japanese Patent Publication No. 2006-067105 (Patent Literature 1) discloses a method in which the routing information indicating the combination of a preset specific communication partner and a specific communication device is previously registered, and a communication route (routing) is set in accordance with the combination. In this method, even when the routing information is updated upon connection to each network, the communication using the specific communication device can be kept for the preset specific communication partner.
In this method, however, the routing information indicating the combination of the specific communication partner and the specific communication device must be previously set in the terminal, and the setting must be changed when the IP address of the communication partner or the IP address of the router included in the routing information is changed.